The invention relates to a finger joint prosthesis made of metal, which consists of a bearing shell, which is attached to a shaft in the metacarpal and which guides a bearing journal that is, attached to a shaft in the phalange. The bearing journal is constructed as a barrel which at right angles to its axis in its center comprises a connecting piece to its shaft.
During their implantation, finger joint prostheses require enormous dexterity of the surgeon, as fingers in the joint region outside the osseous tissue only comprise a few blood vessels, the ligaments required for movement, the nerves required for tactile sense and also surrounding skin. So as not to endanger the supply to the external finger part, the parts outside the osseous tissue should be impaired in their function as little as possible in the proximal direction. At the same time the joint replacement should imitate the natural range of movement as far as possible.
In U.S. Pat. No. 4,293,963 there is described an artificial elbow joint in which a limited mediolateral swivel movement and a bending and stretching movement are achieved, extreme mediolateral swivel movements of the axis of a metal bearing journal being limited by lateral walls at a bearing shell made of polyethylene. The bearing shell is cut back so that the bearing neck can be moved radially in and out. The shown type of bearing can be altered to a finger joint prosthesis, in which case firstly it occupies a large volume and secondly the joint is not secured in the joint capsule in the radial direction.